The present invention relates to an electric parking brake system and a method for controlling the electric parking brake system.
An electric parking brake system mounted, for example, to a vehicle includes an electric motor as a power source and applies braking force to wheels. Japanese Laid-Open Patent Publication No. 13-039279 discloses a method for controlling electric brakes incorporated in an electric parking brake system. A drive current or voltage applied to the motors is subjected to feedback control so that torque generated by the motors is controlled. Accordingly, the braking force applied to the wheels is controlled.
The feedback control complicates the structure and the procedures, which increases the costs. Also, abrupt changes of the load on the motors and inertial force generated based on the rotation of the motors hinder the motors from generating stable braking force.